The fit test panels currently used for respirator research, design, and certification are 25-subject panels developed by Los Alamos National Laboratory (LANL) and are based on data from the 1967 and 1968 anthropometric surveys of U.S. Air Force personnel. Military data do not represent the great diversity in face size and shape seen in civilian populations. In addition, the demographics of the U.S. population have changed over the last 30 years. Thus, it is necessary to assess and refine the LANL fit test panels. This paper presents the development of new respirator fit test panels representative of current U.S. civilian workers based on an anthropometric survey of 3,997 respirator users conducted in 2003. One panel was developed using face length and face width (bivariate approach) and weighting subjects to match the age and race distribution of the U.S. population as determined from the 2000 census. Another panel was developed using the first two principal components obtained from a set of 10 facial dimensions (age and race adjusted). These 10 dimensions are associated with respirator fit and leakage and can predict the remaining face dimensions well. Respirators designed to fit these panels are expected to accommodate more than 95% of the current U.S. civilian workers. Both panels are more representative of the U.S. population than the existing LANL panel and may be appropriate for testing both half-masks and full-face piece respirators. Respirator manufacturers, standards development organizations, and government respirator certification bodies need to select the appropriate fit test panel for their particular needs. The bivariate panel is simpler to use than the principal component analysis (PCA) panel and is most similar to the LANL panel currently used. The inclusion of the eight additional facial measurements allows the PCA panel to provide better criteria for excluding extreme face sizes from being used. Because the boundaries of the two new panels are significantly different from the LANL panel, it may be necessary to develop new respirator sizing systems. A new five-category sizing system is proposed.
Sizing data generated by the military for use in fitting respirators have been the normative basis for commercial respirator sizing. Anthropometric data developed for males and females of military age in the 1950s and 1960s are still in use today and form the only comprehensive body of information available on this subject. The twofold objective of this study was to: (1) develop an anthropometric database detailing the face size distributions of respirator users using both traditional measurement methods and three-dimensional scanning systems; and (2) use the database to establish fit test panels to be incorporated into the National Institute for Occupational Safety and Health's respirator certification and international standards. A stratified sampling plan was used with three age strata, two gender strata, and four race/ethnic group strata. The plan called for an equal sample size of 166 in each cell. Subjects were obtained at 41 sites from 8 states. In addition to height and weight, 18 facial dimensions and neck circumferences were measured using traditional methods. A total of 3997 subjects were measured using traditional methods, and 1013 of them were also scanned using a 3-D head scanner. As this was a volunteer sample, subjects did not appear in the specific proportions needed for the sampling plan. The resulting data were weighted to correspond to the U.S. population. This article presents the summary statistics for the traditional measurement data only. Multivariate analyses of the data from this study and military data revealed that using historical, military data would be inadequate for describing the anthropometric variability of the current U.S. work force.
The microscopic determination of age at death in human bone is a widely used technique in forensic anthropology. Despite its use, little attention has been given to the reliability of microscopic aging when the subject has been burned, either at the time of death, or after death. This preliminary report examines some of the variables of the burning process that may affect the age estimates. Preliminary conclusions arc: (1) bone burned at 600°C retains all of the structures necessary for microscopic aging and (2) bone shrinkage, widely reported in the literature, does not appear to have significant effect on the age estimate. A research plan is outlined that will address some of the questions left unanswerable in the present report.
ProiE>C't lnC' u.s. Army Natick RD&E Center 6c. ADDRESS (City, State, and ZIP Code) 7b. ADDRESS (City, State, and ZIP Code) 0 OTIC USERS UNCLASSIFIED 22a. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) T22c. OFFICE SYMBOL Dr. Claire C. Gordon 617-651-5429 STRNC-YBF DO FORM 1473,84 MAR 83 APR ed1t1on "'ay be used unt1l exhausted. SECuRITY CLASSIFICATION OF ':'HIS PAGE All other editions are obsolete. UNCLASSIFIED l' PREFACE This handbook was prepared as a training document for members of the measuring team who collected the anthropometric and demographic data in the 1987-1988 Army survey. It is intended, in addition, to serve future anthropometrists and researchers as a detailed record of how the data in this landmark survey were obtained.
The adverse effects of interobserver error on morphometric population comparisons are well documented in the literature. While interobserver error can rarely be avoided, it can be minimized by having a single individual locate and mark relevant landmarks, by limiting the number of observers for each variable, and by reviewing repeated measures data daily to catch and correct measurer drift during data collection. In this study, two pairs of experts participated in interobserver error trials designed to pre-set observer error limits for use in the quality control of a large scale anthropometric survey. Repeatability data were also collected twice daily in the field and reviewed with the measurers. Interobserver errors obtained in the field were lower than those achieved by the experts for 27 of 30 dimensions. These results suggest that establishment of permissible interobserver error in advance of data collection and frequent review of repeated measurements during data collection can reduce the magnitude of interobserver error below that obtained by experts measuring in a laboratory setting. However, even differences of small magnitude can be serios when they are directional, and 17 of 30 dimensions exhibited statistically significant bias between measurers despite all quality control efforts. The magnitudes of interobserver error observed in this study have proven particularly useful in evaluating the biological relevance of statistically significant differences which are of relatively small magnitude.
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